Revert "Use a single file for app snapshots."

runtime/include/dart_api.h

Index: runtime/include/dart_api.h
diff --git a/runtime/include/dart_api.h b/runtime/include/dart_api.h
index 45a84008b974b2ab3e550712be463bdd672389c0..c9c0d1a926e4168cc5ed4f11adbb7496f80109e2 100755
--- a/runtime/include/dart_api.h
+++ b/runtime/include/dart_api.h
@@ -3115,6 +3115,10 @@ DART_EXPORT Dart_Handle Dart_Precompile(
  * \return A valid handle if no error occurs during the operation.
  */
 DART_EXPORT Dart_Handle Dart_CreatePrecompiledSnapshotAssembly(
+    uint8_t** vm_isolate_snapshot_buffer,
+    intptr_t* vm_isolate_snapshot_size,
+    uint8_t** isolate_snapshot_buffer,
+    intptr_t* isolate_snapshot_size,
     uint8_t** assembly_buffer,
     intptr_t* assembly_size);